Wide range and tunable linear TMR sensor using two exchange pinned electrodes

B. Negulescu (1) , Daniel Lacour (1) , F. Montaigne (1) , A. Gerken (2) , J. C. Paul (2) , V. Spetter (2) , J. Marien (2) , C. Duret (3) , M. Hehn (1)

1 IJL - Institut Jean Lamour
2 Sensitec GmbH
3 SNR - SNR Roulements

A magnetic tunnel junction sensor is proposed, with both the detection and the reference layers pinned by IrMn. Using the differences in the blocking temperatures of the IrMn films with different thicknesses, crossed anisotropies can be induced between the detection and the reference electrodes. The pinning of the sensing electrode ensures a linear and reversible output. It also allows tuning both the sensitivity and the linear range of the sensor. The authors show that the sensitivity varies linearly with the ferromagnetic thickness of the detection electrode. It is demonstrated that an increased thickness leads to a rise of sensitivity and a reduction of the operating range.

Mots clés: magnetic field sensor; TMR; AlOx tunnel junction; sensitivity; linearity range; IrMn; exchange bias; blocking temperature

Domaines: Science des matériaux [cond-mat.mtrl-sci]

B. Negulescu, Daniel Lacour, F. Montaigne, A. Gerken, J. C. Paul, et al.. Wide range and tunable linear TMR sensor using two exchange pinned electrodes. Applied Physics Letters, 2009. ⟨hal-00397879⟩